In general, a terminal for a battery in which a plurality of members made of different metallic materials are bonded to each other is known. Such a terminal for a battery is disclosed in Japanese Patent Laying-Open No. 2001-6746, for example.
In Japanese Patent Laying-Open No. 2001-6746, there is disclosed a lithium ion battery including a battery can made of Al for functioning as a positive electrode, a clad body (positive electrode terminal) whose one surface side is welded to the battery can while a lead (battery terminal connecting plate) made of a metallic material such as Ni, copper, Ni-platted copper, an Ni alloy or a copper alloy is welded to another surface side and a negative electrode terminal connected to a negative electrode in a state insulated from the battery can. In the clad body of this lithium ion battery, an Al layer and an Ni layer are bonded to each other so that the Al layer (first metal layer) is positioned on one surface side welded to the battery can and the Ni layer (second metal layer) is positioned on another surface side to which the lead is welded. Thus, Ni and Ni larger in electrical resistance than Al are welded to each other, whereby it becomes possible to easily weld the lead and the clad body to each other by resistance welding. It is conceivable that the technique of connecting the lead and the positive electrode to each other through the clad body employing the metallic material easily weldable to the lead and the metallic material easily weldable to the positive electrode material in this manner is applicable also to a case of connecting the lead and the negative electrode to each other. Although not clearly described in Japanese Patent Laying-Open No. 2001-6746, it is conceivable that the clad body is in such a state (overlay (OVERLAYS) shape) that the Al layer and the Ni layer are bonded to each other over the whole surfaces.